Update idlsync.py to pull in dependencies required for chrome api generation.

third_party/chrome/tools/json_schema_compiler/json_schema_test.py

 #!/usr/bin/env python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import json_schema
 import json_schema_test
 import unittest
 
 class JsonSchemaUnittest(unittest.TestCase):
@@ skipping 59 matching lines @@
           }
         }
       }
     ]
 
     schema = json_schema.CachedLoad('test/json_schema_test.json')
     self.assertEquals(compiled, json_schema.DeleteNocompileNodes(schema))
 
 if __name__ == '__main__':
   unittest.main()